The present invention relates to an alignment jig for use in attaching nocks on archery arrows.
Archery arrows presently manufactured are made as metals tubes forming the arrow shaft. At the front end, the shaft end is provided with a point while guide fins are attached adjacent the rear end. The rear end of the shaft is made in a conical shape. Mounted thereon, usually by cementing, is a so called nock provided with a groove for the bow string. The nock is made of plastic and may be damaged or destroyed during repeated use of the arrow. This breakage occurs usually by hitting other arrows at the target. Damaged nocks have to be replaced, which has turned out to be a difficult job, particularly during outdoor competitions.
It is of great important, particularly in competition target archery, that the nock be properly aligned with the shaft. Mis-alignment by as little as a few thousandths of an inch may cause the point of impact on the target to be affected by as much as six inches at 40 yards. When replacing damaged nocks with new ones, the archer must remove fragments of the old nock and cement from the shaft end, apply a small quantity of suitable cement to said end and then press the new nock onto the shaft and taper before the cement has dried. The nock is first rotated until the nock groove is aligned at a right angle to the upper fin (referred to by archers as the "cook fin") and the nock is then checked for straightness before the cement has set. This process can be carried out in two ways.
Firstly, the arrow can be rolled on a flat smooth surface and visually watched for any wobble. Alternatively, the arrow can be spun by resting the shaft on the finger nails of the thumb and middle finger (with the point against palm of other hand) and blowing against the fins. Upon visual observation, if the nock is properly aligned it will spin without any wobble. The precision of the manual spinning and visual observation methods of the nocks for wobbling has become insufficient, particularly for competition purposes. There is thus a need for a opto-mechanical device for assisting in checking the correct alignment of the nock for parallelism with the arrow shaft.
In the past, only one attempt has been made to obtain such an alignment check device. This device is in the form of an indicator having an alignment pin which is introduced in the nock groove. The accuracy of the checking operations carried out by means of this device is still insufficient compared to the accuracies obtained with the present manufacturing methods.